A container ship smashed into a four-lane bridge in the U.S. port of Baltimore in darkness on Tuesday, causing it to collapse and sending cars and people plunging into the river below.Rescuers pulled out two survivors, one in a "very serious condition," and were searching for more in the Patapsco River after huge spans of the 1.6-mile (2.57 km) Francis Scott Key Bridge crumpled into the water.